The present invention relates to the application of thyristor chopper apparatus for determining the propulsion power and electric brake operations of a transit vehicle having series propulsion motors, and more particularly to control apparatus including a microprocessor that is programmed for the desired control of such thyristor chopper apparatus.
Direct current power has been supplied to the series propulsion motors of a transit vehicle with a thyristor chopper, such as disclosed in U.S. Pat. No. 3,530,503 of H. C. Appelo et al, for controlling the acceleration and speed of the vehicle by turning the propulsion motor current ON and OFF in a predetermined pattern. The thyristor chopper can provide either regenerative braking or dynamic braking when braking is desired.
In an article entitled Automatic Train Control Concepts Are Implemented By Modern Equipment published in the Westinghouse Engineer for September 1972 at pages 145 to 151, and in an article entitled "Propulsion Control For Passenger Trains Provides High Speed Service" published in the Westinghouse Engineer for September 1970 at pages 143 to 149, there is described the operation of the P signal for controlling all powered vehicles in a train to contribute the same amount of propulsion or braking effort.
In an article entitled Alternative Systems For Rapid Transit Propulsion And Electrical Braking, published in the Westinghouse Engineer for March, 1973, at pages 34-41, there is described a thyristor chopper control system for propulsion and electrical braking of transit vehicles. The thyristor chopper provides a propulsion system that is superior in smoothness and ease of maintaining a given speed, which latter feature is desired for automatic train control. Moreover, the thyristor system makes regenerative braking practical because the response is fast enough to continuously match regenerated voltage to line voltage, and that matching prevents excursions in braking current and torque due to sudden transients in line voltage. The reduction in power consumption that results from regenerative braking can be significant, but another advantage is in relation to minimizing heat input to tunnels otherwise caused by dynamic braking.
The use of presently available microprocessor devices, such as the Intel 8080 family of devices, is described in a published article entitled "Microprocessors-Designers Gain New Freedom As Options Multiply" in Electronics Magazine for Apr. 15, 1976 at page 78 and in a published article entitled "Is There A High-Level Language In Your Microcomputer's Future?" in EDN Magazine for May 20, 1976 at page 62.